Author Topic: Getrag 240 Torque Limit Found (Read 22614 times)

rob_e30 · « **on:** March 22, 2011, 07:13:11 AM »

After going through 2 Getrag 240's in roughly 3 track days, I feel that we can say for sure that the torque limit of a Getrag 240 is somewhere around 300 ft.lbs. Keep in mind that we run 255 tires on 17 inch rims, and they're pretty sticky Nitto NT01 DOT R tires. With no wheel spin in 3rd gear we've managed to destroy two transmissions while on the track. Both had new Royal Purple oil.

Your mileage may vary... A street car will have less sticky tires that are likley narrower so you may get wheel spin before you crush your transmission.

We will be going to an E36 ZF tranny. That being said, we have a Getrag 260 and 2 more 240's that should work, if anyone is interested.

jscribble · « **Reply #1 on:** March 22, 2011, 07:34:05 AM »

Bummer man. Any tricks needed for the e36 trans to fit/bolt up?

rob_e30 · « **Reply #2 on:** March 22, 2011, 08:59:04 AM »

Quote from: jscribble;102483

Bummer man. Any tricks needed for the e36 trans to fit/bolt up?

It should bolt up and be the proper orientation. We'll have to customize the prop shaft to get it the proper length. We've got to figure out the correct TOB as well.

wazzu70 · « **Reply #3 on:** March 22, 2011, 12:51:16 PM »

Rob, bummer on finding the limit but at least you know that you HAVE to upgrade to a heavier trans now and aren't just doing it "because". The ZF should treat you nicely.

Also, thanks for letting people know. I will have to rethink using the G240 now :cool:

When I was looking into this before I made a nice chart of gear limited speeds for different combinations of trans/188mm R&P

Keep pushing limits!

E30PQ · « **Reply #4 on:** March 22, 2011, 01:18:13 PM »

Video clips from the weekend coming soon.

RoadWarrior · « **Reply #5 on:** March 22, 2011, 05:24:16 PM »

Interested in install pics....!

jscribble · « **Reply #6 on:** March 23, 2011, 08:50:49 AM »

Please do share the details of stuffing the zf in. I'm certain many of us would be interested in upgrading, and custom 6 speeds are a bit out of my range.

Are you going to change your diff ratio for the 1:1 zf final?

EDIT: From an old thread on bf.c

From all the searching I've done today, I've been able to come up with a few things. It seems that there were just two transmissions available to US spec cars, the ZF S5D 310 Z and ZF S5D 320 Z. According to the '95 M3 technical reference, the three digit number indicates the torque rating in Nm. Those numbers then correspond to 229 and 336 ft-lbs. Obviously then, 96-on M3's had their transmissions replaced with the 320 Z transmission because of the increase in torque to 236 ft-lbs.

Truth?

wazzu70 · « **Reply #7 on:** March 23, 2011, 01:20:49 PM »

Yes, you want the later model ZF (was available in the 328s as well as the M3). You can find lots of info on reconditioning the trans before you swap it in as well. There are update parts available.

Shouldn't require anything special to drop in, many people have done it.

You will most likely want to change final drive ratios unless you like ultra short gearing. Thats why I included the chart...to see what you should swap to.

wannam42 · « **Reply #8 on:** March 25, 2011, 10:11:04 AM »

Rob, what diff were you running at the time?

rob_e30 · « **Reply #9 on:** March 25, 2011, 10:22:16 AM »

We run a 3.64 diff. We'll likely need something with a taller rear end, depending on the track. I think the 3.64 will be fine for Buttonwillow and Chuckwalla.

Hey-u · « **Reply #10 on:** March 25, 2011, 03:29:06 PM »

What is the adavantage of ZF over Getrag 6 speed?

wazzu70 · « **Reply #11 on:** March 25, 2011, 06:58:52 PM »

The 6spd is expensive, the ZF is dirt cheap and plentiful

Slick92GS-R · « **Reply #12 on:** March 25, 2011, 07:15:04 PM »

Thank you .. this chart is very helpful & interesting !! Cheers to you, Sir!

NisseJ�rnet · « **Reply #13 on:** April 10, 2011, 05:37:37 AM »

Quote from: rob_e30;102480

After going through 2 Getrag 240's in roughly 3 track days, I feel that we can say for sure that the torque limit of a Getrag 240 is somewhere around 300 ft.lbs. Keep in mind that we run 255 tires on 17 inch rims, and they're pretty sticky Nitto NT01 DOT R tires. With no wheel spin in 3rd gear we've managed to destroy two transmissions while on the track. Both had new Royal Purple oil.

Your mileage may vary... A street car will have less sticky tires that are likley narrower so you may get wheel spin before you crush your transmission.

We will be going to an E36 ZF tranny. That being said, we have a Getrag 260 and 2 more 240's that should work, if anyone is interested.

Are you sure its not because of high oil temp?

rob_e30 · « **Reply #14 on:** April 11, 2011, 08:20:26 AM »

While we cannot be certain, we don't think it's temp related. The second failure happened on the first timed lap of the morning session so the transmission did not get a chance to heat up. The transmission had brand new oil in it so I'm certain it was full and clean.